Evaluation of Outpatients with Suspected Pulmonary Tuberculosis in a High HIV Prevalence Setting in Ethiopia: Clinical, Diagnostic and Epidemiological Characteristics

Abstract

In a setting with a high prevalence of HIV we studied (i) the prevalence of pulmonary tuberculosis (PTB) and HIV; (ii) clinical and epidemiological characteristics of PTB; and (iii) the usefulness of standard procedures for diagnosing PTB. Of 509 consecutive outpatients evaluated on clinical suspicion of PTB in Addis Ababa, 33.0% were culture-verified as having PTB. PTB patients, non-TB patients and controls were HIV-1-positive in 57.1%, 38.5% and 8.3% of cases, respectively. Predictors for culture-verified PTB were age < 25 y, male gender and the presence of HIV and fever, whereas profound weight loss indicated HIV infection. Diagnosis of PTB based on clinical symptoms, sputum microscopy for acid-fast bacilli and chest radiography was sensitive (86.7%) but unspecific (64.1%). In HIV-positive patients both sensitivity and specificity were significantly lower (p < 0.05). HIV-related pulmonary infections are often misinterpreted as smear-negative PTB. HIV screening is therefore warranted not only in cases of verified TB but also as part of the diagnostic work-up in patients with respiratory symptoms suggestive of PTB. Also, increased awareness of, and improved diagnostic tools for, HIV-related pulmonary infections other than PTB are required, together with algorithms for patients with suspected PTB.

Clinical and radiographic features of HIV-related pulmonary tuberculosis according to the level of immunosuppression

“…All patients with CD4+ T-lymphocyte counts < 200 cells/mm 3 presented radiological patterns that were different from the post-primary ones. These results are in accordance with other studies, where cavitation 19 20 , post-primary or typical tuberculin radiological patterns 9 were correlated with CD4+ T-lymphocyte counts > 200 cells/mm 3 and lymphadenopathy and atypical findings with lower counts 9 19 20 .…”

“…The reported weight loss was significantly lower in the group with a CD4+ T lymphocyte count > 200 cells/mm 3 . This had been expected, taking into account that this symptom is frequently found in patients with an advanced stage of HIV infection, regardless of tuberculosis coinfection.…”

“…The ages of the patients ranged from 22 to 58 years, with a mean age of 32.68 ± 7.65 years. The CD4+ T-lymphocyte count ranged from one to 558 cells/mm 3 , with a mean of 168.5 ± 172.6 cells/mm 3 . Eleven (28.9%) patients presented a CD4+ T-lymphocyte count greater or equal to 200 cells/mm 3 .…”

“…The CD4+ T-lymphocyte count ranged from one to 558 cells/mm 3 , with a mean of 168.5 ± 172.6 cells/mm 3 . Eleven (28.9%) patients presented a CD4+ T-lymphocyte count greater or equal to 200 cells/mm 3 . Regarding educational levels, 7.9% were illiterate but most (65.8%) had concluded elementary school.…”

Tuberculosis and HIV co-infection in children

“…Infants of mothers with active TB are at high risk of acquiring TB infection (usually postnatally) and developing active disease [79]. The extrapulmonary forms of the disease, miliary and meningeal TB, are greater risk factors for congenital TB [80]. In one study, at least 15% of mothers with active TB in pregnancy had transmitted infection to their infants by age three weeks [81].…”